Compensated voltage-regulator system



April 10, 1928. 1,665,918

R.D.EVANS ETAL COMPENSATED VOLTAGE REGULATOR SYSTEM Filed March 15. 1923 INVENTORS .WITNESSES- Haber? D. Evans 7 r o ms K. Sels.

W ATTORNEY Patented Apr. 10, 1928.

UNITED STATES PATENT OFFICE.

ROBERT EVANS AND HOLLIS K. SELS, OF PITTSBURGH, PENNSYLVANIA, ASSIGNORS TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF IPENNSYLVANIA.

COMPENSATED VOLTAGE-REGULATOR SYSTEM;

Application filed March 15, 1923.

Our invention relates'to regulator systems and is has special relation to systems for maintaining substantially constant conditions upon. a power circuit.

()ne object of our invention is to so compensate for the action of regulator mechanism of the above-indicated character as to maintain operating conditions of maximum efiiciency upon a power circuit.

Another object of our invention is to provide means to compensate for the action of a voltage regulator of the above-indicated character to maintain eflicient operating conditions at all loads.

In an article entitled Circle diagrams for transmission systems, published in the December, 1921, issue of the Electric Journal (volume 18 No. 12), pages 530 to 536 inclusive, we describe fully a graphical method of calmllating and solving transmission problems and clearly setting forth the conditions obtaining upon a power circuit having a constant generator voltage and a variable receiver voltage, and vice versa. It is further demonstrated that the latter condition permits the use of compensated voltage regulation to reduce the size of the condenser at the receiver end of the circuit and to improve the voltage conditions of the circuit for the entire range of load variations. The article further proves, mathematically and graphically, that the same calculations apply at both ends of the power circuit, so that the herein described method of compensating for the action of a voltage regulator will apply, regardless of whether the voltage regulation is being effected at the generator end or at the receiver end of the circuit.

From a calculated point of maximum efficiency of the circuit, various efiiciency circles may be generated corresponding to various loads. For a transmission system to operate at the most efiicient points throughout the range of load, it is necessary to compensate for the voltage regulation at the generator so that the receiver voltage shall be maintained at the point of maximum efiiciency.

The degree of compensation required is fixed by the constants of the circuit and the operating conditions assumed.

Since the most efiicient compensation is dependent upon the kilowatt load of the power circuit, the single figure of the accompanying drawing discloses a well-known Serial No. 625,281.

form of voltage regulator, the normal action of which is varied by the operation of a watt-meter element that is adaptedqto vary the amount of resistance in circuit with said regulator.

Referring more specifically to the drawing a generator is illustrated. at 1 and a synchronous condenser at 2, respectively representing the generator and the receiver ends of a transmission line 34, 35 and 36. The present invention is described as applied to the voltage regulator for the generator, but as indicated above, it may be applied equally well to the voltage regulator for the condenser.

The generator 1 comprises an armature 2 and a field-magnet winding 3, in circuit with which is an exciter 4 having an armature 5 and a field-magnet winding 6. A well known form of vibratory voltage regulator is illustrated at 7 and comprises a main op-- erating electromagnet 8, a vibrating electromagnet 9 and contact members 11 controlled thereby and governing the operation of relays 12 and 13. The relay 13 periodically short circuits a resistor 10 in circuit with the vibrating electromagnet 9. The relay 12 periodically short circuits a resistor 14 in circuit with the field-magnet winding 6 of the exciter 4 to control the excitation of the main generator 1.

The regulating system thus far described will function to maintain a constant generator voltage and, with the aid of the synchronous condenser, will maintain a constant line voltage.

However, as pointed out above, in order to maintain maximum efliciency of the line at all loads, the action of the voltage regulator must be compensated for in accordance with the kilowatt load. of the circuit being regulated. Accordingly, we provide an elect-romagnet 16 having a centrally located polarizing coil 17 and two currentooils 18 and 19 that are respectively disposed on opposite sides of the coil 17. The current coils 18 and 19 are energized from cross-connectcd series transformers 21 and 22, respectively in circuit with conductors 34 and 36.

The electromagnet 16 actuates a pivoted lever 23 to govern the action of contact member 24, which co-operates with a variable resistor 25 that is located in circuit with the operating coil 8 of the voltage regulator 7. The electromagnet .16 will function to govern the value of the resistor 25 in circuit with the regulator 7 when load is applied to the transmission line to maintain the system in operation at a slightly lagging powerfactor which has been found to be the most efficient condition.

In. general, the efficiency of a transmission system increases very rapidly at first with small, low power-factor loads, then reaches a maximum and falls off gradually to full load, which is probably at leading powerfactor. Similarly, for a constant impedzuice load, the variation ofefliciency with powerfactor is rapid at first, increasing with low, lagging POWGliZLCtOlS, reaching a maximum before unity power-factor is attained and gradually decreasing at an ever-increasing.

rate as the power-factor leading decreases.

Modifications in the system and arrangement and location of parts may be made Within the spirit and scope of our invention, and such modifications are intended to be covered by the appended claims.

We claim as our invention:

1. I11 a regulator system, the combination with a power circuit, and a dynamo-electric machine, of a regulator therefor comprising a pair of electromagnets actuated in accordance with the voltage of said power cirouit, a variable resistor means in circuit with said electromagnets, and means actuated in accordance with the load upon said power circuit to control said variable resistor means.

2. In a regulator system, the combination with a power circuit, and a dynamo-electric machine, of a regulator therefor comprising a pair of electromagnots actuated in accordance with the voltage of said. power circuit, a variable resistor means in circuit with said clectromagnets, and means actuated in accordance withthe watts of said power circuit for controlling said variable resistor means.

3. In a regulator system, the combination with a power circuit, a dynamo-electric machine connected thereto and means for varying the operation of said machine, of regulator means therefor comprising independent elements actuated in accordance with the voltage and the watts of said circuit.

1. In a regulator system, the combination with a dynamo-electric machine of regulator means therefor comprising independent elements actuated in accordance with the voltage and the watts of said machine.

In testimony whereof, we have hereunto subscribed our names this 7th day of March, 1923, and this 27th day of February, 1923, respectively. I

ROBERT D. EVANS. HOLLIS K. SELS; 

